A motor vehicle's on-board diagnostics (OBD) system provides self-diagnostic and reporting capability that can enable a vehicle owner or mechanic to access information about the engine and other vehicle sub-systems. All new motor vehicles are now equipped with a standard OBD-II or EOBD connector in line with regulations in force since 1996 in the USA, since 2000 for new passenger cars and LCVs in the EU, and since 2004 for HGVs in the EU. The OBD connection port in a vehicle can provide real-time engine data in addition to standardised diagnostic trouble codes which allow a mechanic to rapidly identify and remedy problems with the vehicle.
More recently, there have become available OBD data collection devices comprising a connector so as to be plugged into a vehicle's OBD port on a long-term basis to receive OBD data for a variety of purposes. For example, the TomTom ecoPLUS™ device can be installed in a vehicle belonging to a fleet so as to provide accurate information on fuel consumption and efficiency which is transmitted to an external server and displayed, for example, to a fleet manager. In another example, TomTom's LINK 100 is an OBD-II Bluetooth dongle that sends data from the vehicle's OBD port to the driver's smartphone so as to provide insurers, car manufacturers, road side assistance or leasing companies with access to usage and driving performance data. An insurance company may, for example, provide an OBD data collection device that plugs into a vehicle's OBD port so as to automatically track driving habits and thereby determine the insurance premium payable. This is known as usage-based insurance (UBI).
An example of a UBI data logging device is described in US 2013/0013348 A1. Such a data logging device includes a microprocessor and wireless GSM transceiver so that vehicle usage information can be transmitted to an insurer or other external entity. WO 2004/040405 A2 provides another example of an OBD data logging module that is configured to plug into the OBD-II port of a vehicle and record data, using engine start to define the beginning of a trip and engine stop to define the end of a trip. The module monitors driver habits and has a wireless communication interface so that OBD data can be transmitted to an external computer for interrogation. Such an OBD module can connect to the 12 V supply of the vehicle battery.
Typically, an OBD device will determine when the vehicle's engine is started or stopped by monitoring the engine revolutions or sensing vehicle voltage. However, it is not always straightforward for the OBD device to interrogate the engine status because several vehicles can provide a misleading response when the engine is turned off and the engine control unit (ECU) is in a low power state. It has therefore been proposed that the OBD device senses the voltage level provided on the OBD connector. The OBD device may be woken from a sleep mode by determining a change of engine state through sensing the voltage level. For example, a voltage above a threshold of 13.2 V may be taken as a clear indicator that the alternator is running to charge the vehicle battery and hence the engine must be running. Sensing a voltage below this threshold suggests the engine has been stopped.
However a rising number of vehicles are now equipped with “smart charging” technology, a form of regulated voltage control, that uses system information to optimise the voltage supplied to the battery. A “smart charging” alternator, controlled by the ECU, may allow the charging voltage to drop below the normal charging range e.g. of 13.8-14.8 V. As the charging voltage may fluctuate while the engine is running, it becomes unpredictable for an OBD device to reliably detect engine state solely based on voltage levels.
Accordingly, there remains a need for an improved OBD data collection device.